For your intentions dull is better ! Forks are not ground penetrating tools . They are intended for lifting and separating hay , straw , grass or in a pinch aerating soil .

Interesting question. Pretty easy to understand why other garden tools should be sharpened, but forks? Seems to me that a sharp fork applied to a buried rock is just an invitation to break off that carefully sharpened edge. As long as you never hit a rock with it, I guess a sharp fork could be valuable in penetrating soil better, but ...

Might say the same thing about a sharp shovel, though a sharp edge on a shovel can be very helpful in slicing through roots. You don't do slicing with a fork.

That makes sense Dan. I think I’ll leave the fork unsharpened!

I have a 'potato fork' that is likely about 100 years old. it digs potatoes and I use it a lot to loosen soil and to aerate soil in spring for faster drying. It is 6 tines I believe and still plenty sharp!